Chester and Dora Fronczak's newborn son, Paul, was kidnapped from a Chicago hospital in 1964 and, supposedly, found safe 18 months later. Paul Fronczak, pictured, learned earlier this year that the identification was false and he is not their son. (KLAS-TV)

Chester and Dora Fronczak's newborn son, Paul, was kidnapped from a hospital in 1964 by a woman posing as a nurse. Eighteen months later, a toddler abandoned in New Jersey was identified as the stolen boy.

Earlier this year, that boy, now a 49-year-old man, learned that investigators were wrong all those years ago. He is not the Fronczaks' biological son.

The Chicago Tribune reported today that Joan Hyde, a spokeswoman for the FBI in Chicago, confirmed the bureau is again looking into the Fronczak abduction. Federal investigators even got a lucky break when they found the original files and evidence in the case.

"It was deemed appropriate to take a fresh look at the evidence that we have and possibly re-interview sources that are still around," Hyde told the paper.

The Fronczak kidnapping made international news when it occurred, and has done so again since Paul Fronczak learned that the real Paul was never found.

Fronczak told The Tribune that he sought DNA swabs from his parents because of nagging suspicions that investigators were wrong in the 1960s. He was reportedly identified as Paul Fronczak because his ears were similar to the missing child, but over the years, he found little resemblance between himself and his parents.

His hunch proved to be right.

Fronczak said his parents support his bid to finally solve the mystery, but that it is too painful to them to be involved.

He has since been trying to find out who he really is. KLAS-TV, the station that originally broke his story in April, has set up a Facebook page dedicated to the case.